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