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