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