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)(16,26)(17,22)(18,24)(19,21)(20,27)(25,28) involution — undirected(5,6)(7,10)(8,9)(11,12)(13,15,18,26,19,25,17,20)(14,16,22,23,21,27,24,28)(1,2,3,4)(6,9)(10,12)(13,16,19,27)(14,20,21,26)(15,24,25,22)(17,28,18,23)(5,7,8,11)(6,10,9,12)(14,21)(15,25)(20,26)(22,24)(13,17,19,18)(14,22,21,24)(15,20,25,26)(16,23,27,28)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.