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