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