This is all Wiki throws up on the subject:
Enterprise has its own unique livery consisting of Dark Grey (NCS 8502-Y), Light Grey (NCS 5502-Y), Dark Green (NCS 9005-G20Y), Bronze strip & Enterprise logos (3M), and either Purple (NCS 5040-R40B) for Standard Class or Dark Red (NCS 4060-R10B) for First Plus.
If that's of any help.