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