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