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