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