Indeed the standard positions do not really allow finger patterns for diatonic scales like you have on guitar, but require a position shift once every three or so notes, unless you use empty strings to fill some gaps. While this may seem, in a practical sense, a bit annoying, cellists tend to make a virtue of it by using the shifts as an expressive feature of their playing. Also, it certainly keeps you well-practiced for when you need to switch positions for other reasons!
But as a cello beginner, you'll have enough to worry about – even without position shifts. (I'd strongly recommend you take at least some proper lessons!) As far a scales are concerned, it's for the beginning best to stay in first position and make use of empty strings. The C-major scale works this way over the entire range, without any stretching needed.
-------------------------0-1-2-
-----------------0-1-2-4-------
---------0-1-3-4---------------
-0-1-3-4-----------------------
(Those are finger numbers, not “frets”!)
G-major and D-major work of course exactly the same way, if you start on the third/second string instead of the low C.
I suppose you won't be very happy with this advice, but it's little use to try and immediately play in any key, if it distracts you from getting the basic technique right. For instance it's vital to get used to proper loose hands and arms, if you ever wish to be able to execute position shifts precise- and smoothly.
Once you're acquainted with the first position, the next thing to learn are occasional shifts to fourth position to extend the range. Then you can start with other positions, which then also opens up other keys.
At some point you may also learn the thumb positions: high up on the neck, you suddenly have enough fingers to play full scale patterns!