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)(11,16)(12,13)(14,15)(25,26,29,32)(27,30,33,37)(28,35,36,31)(34,40,39,38)(1,2,4,5)(3,7,8,6)(9,11)(10,13)(12,14)(15,16)(17,18,21,20)(19,23,24,22)(27,33)(30,37)(34,39)(38,40)(2,5)(6,7)(10,15)(11,12)(17,19,21,24)(18,22,20,23)(25,26)(27,30)(28,31)(29,32)(33,37)(34,38)(35,36)(39,40)(1,2)(3,6)(4,5)(7,8)(9,12,14,11)(10,16,15,13)(25,27,29,33)(26,30,32,37)(28,34,36,39)(31,38,35,40)(1,3,4,8)(2,6,5,7)(9,13,14,16)(10,11,15,12)(17,20,21,18)(19,23,24,22)(25,28,29,36)(26,31,32,35)(27,34,33,39)(30,38,37,40)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.