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