One vertex per element, one color per generator, with an edge from x to x·s.
(1,2) involution — undirected(4,8)(5,6)(9,10)(11,12,15,21,16,22,30,36,17,19,31,37,29,38,14,20)(13,23,25,33,26,39,24,40,27,41,28,18,32,34,42,35)(3,4)(5,8)(6,10)(7,9)(11,13)(12,18)(14,28)(15,24)(16,32)(17,27)(19,33)(20,39)(21,23)(22,40)(25,30)(26,29)(31,42)(34,36)(35,38)(37,41) involution — undirected(3,5,7,6)(4,8,9,10)(12,19)(18,33)(20,36)(21,37)(22,38)(23,41)(34,39)(35,40)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.