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