One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,6)(7,10)(8,11)(9,12)(13,20)(14,18)(15,17)(16,19)(21,22)(23,30)(24,32)(25,28)(26,35)(27,31)(29,34)(33,36) involution — undirected(1,2,4,3)(5,7)(6,10)(8,15)(9,14)(11,17)(12,18)(13,16)(19,20)(21,23,25,31)(22,27,28,30)(24,26,33,34)(29,36,35,32)(5,8)(6,11)(7,13,14,15)(9,16)(10,17,18,20)(12,19)(21,24,26,31,25,33,34,23)(22,27,29,32,28,30,35,36)(1,3,4,2)(8,16)(11,19)(13,15)(17,20)(22,28)(27,30)(29,35)(32,36)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.