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