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