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