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