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