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