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