One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,6)(7,10)(8,16)(9,15)(11,13)(12,20)(14,18)(17,19)(21,22)(23,27)(24,28)(25,33)(26,29)(30,36)(31,34)(32,35) involution — undirected(1,2)(3,4)(5,7,10,6)(8,17,19,16)(9,15,11,13)(12,18,14,20)(21,23)(22,27)(24,31)(25,30)(26,32)(28,34)(29,35)(33,36)(1,3,4,2)(5,8,10,19)(6,12,7,14)(9,18,11,20)(13,17,15,16)(23,30)(24,25)(27,34)(28,33)(31,32)(35,36)(5,9,10,11)(6,13,7,15)(8,18,19,20)(12,17,14,16)(21,24,26,25)(22,28,29,33)(23,31,32,30)(27,34,35,36)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.