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