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