lol, my wild guess on her colors... actually I don't expect her to have that scheme in canon, but I had fun using some of my favorite colors anyway
I wanted to give her an ancient feeling, like she could be some powerful witch from old times, and at the same time with a touch of royalty!
So there I choose purple and red for her robes, to make it as majestic as possible... and golden is always a nice complement to royal characters
I colored her hair white since it seems the sage had very fair hair color an it goes well with her robes... I just made the eyes glowing red to represent the powers she got and I saw in the panels she had a strong line over her eyes, so I thought it could be some make-up, and it helps giving her an ancient touch
Hope you like it