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