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