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