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