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