But remembering which color means which person is just as hard as remembering which icon means which person. If you don't want to put names under the icons, how about putting a list in the ingame help that shows the icons with names next to them?
The in-game guide shows each character, and they all have different colored circle icons. The orrery shows each character and they have different colored names. When each character talks their name is shown as a certain color. However, the color posted above is the official colors of each character