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