You can represent visible star colours pretty accurately, but most choose to accentuate the saturation a bit in imaging - they are actually only moderately colourful.
This is the best site I have come across on actual star colours.
http://www.vendian.org/mncharity/dir3/starcolor/
as you say Greg, local atmospheric and galactic dust effects can alter these - for example, it is not unusual for stars to appear more red looking than they should be and to have bluish scatter halos.