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