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