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