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