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