This is a simple graphical replacement for the Group Role icons. The Tank icon has been replaced with the shield icon from the Cleric buff line. The Assist icon is a pair of crossed swords from item icons. The Puller icon is also from a spell icon.

The image above is a degraded JPG image; the icons look better in game when used on a solid window. If you use a transparent window, or have lots of decoration on the group window, this probably won't look as good.