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