Color Code Each State

I need to mark the US with different colors in sets of states based on the coverage various trucking companies have. In other words, each trucking company will have its own color in each state.
How do I do that?

Go to Data | Territories, then Create Manually and choose State.

Then, click on the name of a state and click the Add to Territory button on the left.

Let me know if you have any difficulty.

Eric