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