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