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)(26,30)(27,33)(28,35)(38,40)(1,3,6,5)(2,4,7,8)(9,10,13,11)(12,14,16,15)(17,18,21,20)(19,23,24,22)(27,33)(31,36)(34,39)(38,40)(2,7)(3,5)(9,10,13,11)(12,15,16,14)(17,19,21,24)(18,22,20,23)(25,26)(27,31)(28,32)(29,30)(33,36)(34,38)(35,37)(39,40)(1,4,6,8)(2,3,7,5)(9,11,13,10)(12,15,16,14)(25,27)(26,31)(28,34)(29,33)(30,36)(32,38)(35,39)(37,40)(1,5,6,3)(2,8,7,4)(9,12)(10,14)(11,15)(13,16)(17,20,21,18)(19,23,24,22)(25,28,29,35)(26,32,30,37)(27,34,33,39)(31,38,36,40)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.