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