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