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