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