For Linux - easy! On DevianArt
'e has theme for XFCE, about GNOME/KDE/Unity do you know if they have it, but to find a site with themes for the desired graph. shell - a breeze. I thought you here this
will do. In extreme cases, find the folder with the theme, like for you and finished it. This is Linux.
About Windows and - here is more complicated. Customization has always been limited. If you do not find the right topic - you just need to get a researcher internal resources of the application(e.g. PE Explorer) to find the theme files, duplicate it and change the icons color.