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