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