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