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