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