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