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