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