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