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