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)(15,20)(16,21)(17,19)(18,22)(23,26)(24,28)(25,27) involution — undirected(1,2)(3,4)(6,9)(10,12) involution — undirected(2,4)(14,19)(16,17)(20,26)(21,22)(23,25)(27,28) involution — undirected(2,4)(13,15,18,24)(14,20,22,28)(16,25,17,23)(19,26,21,27)(5,7,8,11)(6,10,9,12)(13,16,18,17)(14,21,22,19)(15,23,24,25)(20,26,28,27)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.