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)(11,20)(12,14)(13,16)(15,17)(18,19)(21,24)(22,23)(25,26,29,32)(27,33,35,30)(28,31,37,40)(34,39,36,38)(1,2,4,6)(3,5,8,7)(9,11,15,13)(10,16,17,20)(12,21,19,23)(14,22,18,24)(25,27)(26,30)(28,36)(29,35)(31,39)(32,33)(34,37)(38,40)(1,2)(3,5)(4,6)(7,8)(10,17)(12,19)(16,20)(21,23)(25,27,29,35)(26,30,32,33)(28,34,37,36)(31,38,40,39)(1,3)(2,5)(4,8)(6,7)(9,12,15,19)(10,18,17,14)(11,21,13,23)(16,24,20,22)(25,27)(26,30)(28,34)(29,35)(31,38)(32,33)(36,37)(39,40)(9,13,15,11)(10,16,17,20)(12,23,19,21)(14,22,18,24)(25,28)(26,31)(27,34)(29,37)(30,38)(32,40)(33,39)(35,36)(9,14,15,18)(10,19,17,12)(11,22,13,24)(16,23,20,21)(25,26)(27,30)(28,31)(29,32)(33,35)(34,38)(36,39)(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.