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