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