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