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