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