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