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