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