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