Originally Posted by Master Finch
Jedi Guardians have Blue Lightsabers, with the exception of The Exile who carried Cyan.
Jedi Consulars have Green Lightsabers.
Jedi Sentinels have [supposedly] Yellow Lightsabers.
Mace Windu was given a rare violet crystal as a reward or something I can't remember it's on his Wookiepedia page.
Yes, BioWare came up with that for Kotor, but they have the Sentinels in TOR using blue by default, since they are an archetype of the Knight class, however with the ability to wield two. The Sentinel will have some options.
As for Mace Windu, that is the in-universe story, yes.
The truth, though, is that Samuel L. Jackson was talking with George during the filming of the Arena Battle from Episode II about what their colors will be in the final film. George said flat-out "good guys are blue and green, bad guys are red." As if, don't challenge me, then Jackson, said, "Can mine be purple [violet]. George puts his hand to his beard and say rather reluctantly, "We can do purple!" And, that was it! To this day, no other Jedi filmed by George Lucas has ever received purple, again.
Hence, my surprise when BioWare gave the color to the Sith Inquisitor, a class that resembles Darth Sidious. (Sidious, mind you had a red lightsaber in the film) So, yeah, I was a bit surprised by that. Notice that none of the cinematics done my ILM have the sith using purple. I'm wondering how they got it in there.
Also, in case you're wondering where my sources lie. Episode II DVD Disc 2, and Lucasfilm, Ltd. FAQs about employment. Does GL visit the campuses? Yes is the paraphrase, but some more often than others.
Do Lucasfilm employees ever see or work with George Lucas?
George is an active participant in all of his businesses and is on one of the campuses every day; he works as hard as we expect you to. Depending on what company you work for, you may see him more or less than other employees.