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)(11,17)(12,16)(13,15)(14,19)(18,24)(20,22)(21,23)(25,26,30,31)(27,32,36,40)(28,37,35,33)(29,34,39,38)(9,11,13,19)(10,14,15,17)(12,20,21,18)(16,24,23,22)(25,27,30,36)(26,32,31,40)(28,34,35,38)(29,37,39,33)(2,5)(6,8)(25,28,30,35)(26,33,31,37)(27,29,36,39)(32,38,40,34)(1,3,4,7)(2,6,5,8)(10,15)(14,17)(16,23)(22,24)(25,26,30,31)(27,32,36,40)(28,33,35,37)(29,38,39,34)(9,12,13,21)(10,16,15,23)(11,18,19,20)(14,22,17,24)(25,29)(26,34)(27,35)(28,36)(30,39)(31,38)(32,33)(37,40)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.