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