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