Buckley Notation Option
While there is an option to color the displayed notes (presumably to aid beginning students), another feature that can help intermediate keyboard students is Buckley Notation.
This was developed by the well-known (although now deceased) polymath, newspaper columnist, talk show host, political analyst, novelist, mystery author, etc. etc. William F. Buckley, Jr. Mr. Buckley, a true Renaissance man, was also an accomplished pianist, and developed a system to assist beginning to intermediate students in their keyboard sight-reading skills. The way it works is that, in any score, all of the accidentals are indicated by a color coded note head - usually one color for sharps and a different color for flats. This is without regard to whatever key signature is in use, so in the key of G, all of the Fs (i.e. F#s) would be shown with a colored note head.
If this were developed, my recommendation would be to allow [all sharps and flats] to be colored, or [only non standard sharps and flats] to be colored (in the latter option, the f# in the key of G would not be colored.) With both options available, the feature could be configured according to the student's progress and/or ability.
Although he published several volumes of "standards" (e.g. Bach's Well Tempered Clavier, a selection of Chopin, etc.), this system never caught on widely. I suspect that had more to do with the cost of producing the scores (there really was no automated way to do this at the time) than its usefulness (which I can attest to), the advent of a non-commercial program like MuseScore (and others like it) might allow teachers and students to benefit from it. Of course, there would have to be an option as to whether or not the notes were colored on any print-outs.