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