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