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