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