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