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