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