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)(15,23)(16,24)(17,19)(18,26)(20,21)(22,25)(27,28) involution — undirected(1,2)(3,4)(6,9)(10,11)(14,19)(15,21)(16,20)(18,25)(23,27)(24,28) involution — undirected(13,15,18,21,17,24,25,28)(14,20,22,23,19,27,26,16)(2,4)(13,16,18,20,17,23,25,27)(14,21,22,24,19,28,26,15)(5,7,8,12)(6,10,9,11)(14,19)(15,24)(21,28)(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.