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