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