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