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