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