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