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