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