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