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