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