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