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