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