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