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