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