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)(11,13)(12,20)(14,15)(16,18)(17,22)(19,23)(21,24)(25,26,32,36)(27,31,29,34)(28,35,30,33)(37,40,38,39)(1,3,5,8)(2,6,7,4)(10,15)(11,18)(17,20)(19,24)(25,27)(26,31)(28,38)(29,32)(30,37)(33,40)(34,36)(35,39)(1,3)(2,4)(5,8)(6,7)(9,11)(10,16)(12,19)(13,15)(14,18)(17,23)(20,21)(22,24)(25,28,32,30)(26,33,36,35)(27,37,29,38)(31,39,34,40)(1,4)(2,3)(5,6)(7,8)(9,11)(10,16)(12,19)(13,15)(14,18)(17,23)(20,21)(22,24)(25,29,32,27)(26,34,36,31)(28,37,30,38)(33,39,35,40)(9,12,14,22)(10,17,15,20)(11,19,18,24)(13,21,16,23)(25,30,32,28)(26,35,36,33)(27,37,29,38)(31,39,34,40)(9,13,14,16)(10,11,15,18)(12,21,22,23)(17,19,20,24)(25,31,32,34)(26,29,36,27)(28,39,30,40)(33,38,35,37)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.