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