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