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)(9,13)(10,14)(12,18)(16,20)(17,19)(21,22,26,30)(23,31,33,36)(24,29,25,28)(27,34,35,32)(2,4)(6,11)(7,16)(8,10)(13,14)(17,18)(19,20) involution — undirected(5,7,9,18)(6,12,13,15)(8,16,10,17)(11,19,14,20)(21,23)(22,27)(24,32)(25,34)(26,33)(28,31)(29,36)(30,35)(6,13)(11,14)(12,15)(19,20)(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.