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