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