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