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