Greens easy to distinguish on the map (unless your red green colour blind) and ROYGBIV is easy to remember for ordering the spectral classes. I stole that from the board game Stellar Conquest a long, long time ago and just stuck with it ever since. Feel free to put correct spectral tints in on your maps. I was brought up on paint colours where reflected light gives red, yellow and blue as primary colours, instead of projected light which has red, green and blue as primary colours.
So, yes, green tint is F and A, blue tint is B and O. I haven't indicated luminosity. There are no N or dwarf stars and no neutron or black hole stars given either.