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