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