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