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