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