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