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