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