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