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