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