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