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