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