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