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