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