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