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