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