The Music Publishers Association of the United States, Inc. publishes a pamphlet called "Standard Music Notation Practice."
In the section "Placement of Note Heads and Accidentals", rule (b) confirms Tim's answer.
(b) Thus in an interval of a second, written on a single stem, the lower note is placed on the left and the upper note on the right.
It goes on to explain,
In the case of the upstem, the lower note is in correct relation to the stem, while with a downstem the opposite is true.
Which means that when writing a chord, notes align on the left side of an upstem (with the "displaced" note on the right) and on the right side of a downstem (with the displaced note on the left).
First inversion G7 chord
It's worth noting (pun intended) that the note placement stems (again) from rule (a), which observes that
Many musical symbols slant up from left to right at a uniform angle. This makes for easier reading. This diagonal principle governs the placement of note heads and accidentals in chords where they cannot be aligned vertically.