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