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