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