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