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