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