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