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