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