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