The Color Scheme Editor is a added utility you will find the SDK folder of your install. It will usually require first the installation of the UserTools.msi. After which you will have a folder called User Tools and sub folders for the additional utilities and commands.
The purpose of having the color scheme editor is for a couple reasons. One I ran into just the other week when I had a visually impaired user that had trouble discerning greens and reds. After I researched how many people are affected by this I started to wonder how many CAD users out there are in need of adjusting their color schemes for this reason or another. More often than not I run into users that dislike the standard color of their work planes or surfaces in their models. This is a way to adjust those items as well.
Before going into the foray of editing default or creating new color schemes you should back up the originals which are in fact registry entries. In the Color Scheme Editor you have a backup pull down, make sure you use the commands there.
You also have to choose which registry you are affecting. Below I have 2009 and 2010 installed and they have different registry versions. Remember this: Inventor Versions
After you have effectively backed up your registry and have chosen the correct one to adjust feel free to experiment away with the options in here to gain the result you desire whether it be comfortable usage or graphically pleasing. After it is created and in your registry it will be available in your Application Options on the Colors tab as an available Color Scheme.
Until next time, may your colors be discernible!