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