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