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