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