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