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