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