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