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