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