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