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