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