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