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