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