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