Playing chords on a guitar is different that playing chords on piano because of the way the notes are laid out on the fret board. Every chord can be played in multiple ways (called voicings) in multiple positions. But most beginning guitar students start by learning the simple open position or first position chords. Also, on guitar you can't just move a shape higher up the keyboard to go from say a Cmaj chord to an Fmaj chord. The fingerings on guitar between those two chords in open or first position are completely different (same applies to most open position chords on guitar).
I learned to "sight read" chords by learning to play songs that were of interest to me. I started with mostly three or four chord songs. To learn to play the songs, I had to learn to play the chords in the voicing most appropriate for the particular song (or the suggested voicing on the sheet music). As a beginning guitarist, I started out learning the easiest to play open position chords.
So if the song I wanted to learn had a G, G7, C and D chord in it, I memorized the fingering for those four chords. Now I could sight read any music that contained those same chords. Later maybe I came across a song that had those chords but also an Em chord. So I learned how to finger a basic Em chord and it stuck in my memory as I continued to play the new song.
It's just a building process of memorizing the fingerings for the various chords, a few at a time, and them applying that knowledge by playing songs using the chords. Kind of like using a new vocabulary word in a sentence helps you remember the word.
So I recommend just learning to play some songs you like - in keys that contain chords that are easy for you to play on guitar, and play those songs often enough to memorize all the fingerings for the chords used in that song. Later you can add variations of those chords and memorize them - one at a time.
Many guitar lead sheets or sheet music publications show the chord diagrams on the sheet music itself so it's easy to refer back to as you learn the song. If you are learning a new song from music that does not have chord charts, you could print the chords you need and have them handy for reference as you learn the chords.
You might want to download a chord chart such as the one on this site (click the link and then download the free e-book called "ultimate guitar chords e-book")
Guitar Chords E-Book
Then if you are learning a new song and it contains a chord you have not learned yet, you can look up the various fingerings for that particular chord and find the one that sounds best that you can actually play without too much difficulty.
If you mean sight read chords by the notes on the staff with no chord letters above the staff, some of the same principals apply. If you know the chords by sight for keyboard, it's just a matter of memorizing the chord fingerings for guitar. Based on your keyboard chord knowledge, you should be able to recognize a G major chord from the notes on the staff. So you just need to memorize the fingering on guitar for the G major chord (whichever voicing you choose). As part of the learning (memorization) process, you might just write the chord names above the chords and copy and paste the chord diagrams you will need into a document and print it out as a cheat sheet until you memorize all the chords used in a particular song you want to learn to play on guitar. Start with a simple three chord song and then build from there.
Hope this helps. Good luck!