One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(9,10,12,18,28,35,31,39,15,17,13,19,14,20,29,37)(11,21,23,40,32,38,30,33,26,22,24,34,25,36,27,16)(2,4)(5,6)(7,8)(9,10,12,18,28,35,31,39,15,17,13,19,14,20,29,37)(11,22,23,34,32,36,30,16,26,21,24,40,25,38,27,33)(6,8)(9,11,15,26)(10,16,17,33)(12,27,13,30)(14,32,28,25)(18,36,19,38)(20,40,35,34)(21,39,22,37)(23,31,24,29)(2,4)(10,17)(16,33)(18,19)(20,35)(21,22)(34,40)(36,38)(37,39) 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.