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