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