The default files, config editor, and manual can be found
here on the NEC website.
I strongly recommend thoroughly reading the manual. It details how to use the Config Editor as well as how to replace the default files if needed.
Did you change the color via the in-hilt color swapping (the wrist flick thing)? If so then you should be able to just cycle back to it. While the saber is on it "remembers" which color the font was last used with, and until you power it off and put the kill key in it will start that font with whatever the last color used was. So if Font 1 is Blue and you change it to Green, then you switch to Font 2 (whatever color) and go back to Font 1, Font 1 will still be using Green. The kill key will "reset" it back to whichever color the settings on the SD card say it should start with. So in that example, if you were to power off, put in the kill key, then pull it out and fire up the saber again Font 1 will again start at Blue.
If you changed the color with the Config Editor on your PC, then one of two things happened:
1) You changed the values of the color profile from blue (255,0,0,0) to purple (255,0,255,0), or
2) You simply changed the color profile that the font starts at.
So if Colr1 was Blue, then you either changed Colr1 to be Purple, or you set Font1 to start at, for example, Colr2 instead of Colr1.
Below is an example with my rBrB/GG Hero saber (or 6w Deep Blue / 6w Green)*. The profile shown is setup for a light mint green with a more sea green flash/deflect color (sectioned in green boxes). This is Font4 on my saber and Colr2 profile; as you can see I've told the Font to start with this color (sectioned in the yellow box) rather than having to cycle to it every time I go to that font.
*because of how my LED is wired, the color sliders on mine are set to Royal Blue - None - Green - None, whereas your RGBA/W saber should be Royal Blue - Green - Red - Amber/White. Using the below settings with an RGB LED would actually make a pink instead of minty green.
(sorry for fuzzy quality, the forum seems to downsample images quite drastically)