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