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