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