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