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