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