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