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