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