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