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