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