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