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