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