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