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