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