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