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