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