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