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