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