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)(11,15)(12,16)(13,17)(14,18)(19,23)(20,22)(21,24)(25,26)(27,33)(28,36)(29,32)(30,35)(31,37)(34,38)(39,40) involution — undirected(2,5)(6,8)(9,11)(10,15)(12,20)(13,19)(14,21)(16,22)(17,23)(18,24)(25,27,29,35)(26,30,32,33)(28,34,37,40)(31,38,36,39)(1,3,4,7)(2,6,5,8)(10,16)(11,19)(12,13)(17,18)(20,21)(22,23)(28,37)(30,33)(31,36)(34,40)(2,5)(6,8)(9,12,14,13)(10,16,18,17)(11,20,21,19)(15,22,24,23)(25,28,29,37)(26,31,32,36)(27,34,35,40)(30,38,33,39)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.