people are going to say that you can already see the color on the galaxy map but I agree with this +1.
I was thinking about this earlier and one of the easiest things to do to make this game more interactive is implement more use of colors as visual queue to stand out against the monochrome UI.
Its already done to a degree with rep/allegiance, hostile/nonhostile. Would be cool to add different colors to the HUD to match the things in the UI like making the font that says their PP faction match the color of their powerplay faction, the system name font match the color of their power (red fed, blue empire, green alliance, yellow indie, etc), or make the font of system type (hitech/agri/etc) match the color or the trade commodity lines. once you kind of memorized the colors you then wouldnt have to keep going back and forth to the galaxy map all the time which slows the gameplay down.
I know some people would hate it but just give the option to turn on/off individually.