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