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