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