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