One vertex per element, one color per generator, with an edge from x to x·s.
(1,2) involution — undirected(3,4,6,5)(7,8,11,17,13,16,12,18)(9,19,21,28,22,32,26,14)(10,15,24,29,23,31,25,30)(20,33,35,37,34,38,36,27)(7,9,12,21,13,22,11,26)(8,14,18,19,16,28,17,32)(10,20,25,35,23,34,24,36)(15,27,30,33,31,37,29,38)(3,5,6,4)(7,10,13,23)(8,15,16,31)(9,20,22,34)(11,24,12,25)(14,27,28,37)(17,29,18,30)(19,33,32,38)(21,35,26,36)(8,16)(10,23)(14,28)(17,18)(19,32)(20,34)(24,25)(35,36) involution — undirectedA 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.