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