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