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