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)(11,22)(12,17)(13,18)(14,20)(15,21)(16,24)(19,31)(23,27)(25,33)(26,39)(28,34)(29,36)(30,37)(32,38)(35,40) involution — undirected(9,11,14,24,15,18,31,25)(10,16,19,22,21,33,20,13)(12,26,29,23,28,38,40,37)(17,27,35,39,34,30,36,32)(2,5)(6,8)(9,12,14,29,15,28,31,40)(10,17,20,36,21,34,19,35)(11,23,25,26,18,37,24,38)(13,30,16,32,22,27,33,39)(9,13,14,16,15,22,31,33)(10,18,20,24,21,11,19,25)(12,27,29,39,28,30,40,32)(17,23,36,26,34,37,35,38)(1,3,4,7)(2,6,5,8)(12,28)(17,34)(23,37)(26,38)(27,30)(29,40)(32,39)(35,36)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.