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