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