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