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