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