Hi,
attached are some versions I tried, to give you all some inspiration.
I couldn't find the base color on the floor that slightly effects the shouts too. I have the strong suspicion that you won't be able to change it with the texture files, like with the base color of the budokai dragons aura.
(Shown Aura in Attachement: Folder Blueish Purple)
You have to replace the +15 charging aura in texture --> effect
Here are some gifs of the different charging auras I've tried