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