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