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