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