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