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