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