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