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