The VW bus was painted by Robert Hieronimus in 1968 for Bob Grimm of the band "Light" which he drove with Rick Peters, Trudy Morgul and Walt Bailey to the original Woodstock in 1969.

Rick (drummer) & Trudy (vocalist) at Woodstock 1969.
Bob stitting atop the bus at Woodstock
Bob with the "Light Bus" and the artist's "bug".
"Light Bus".
The other side of the bus
[via Damn Cool Cars]