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