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