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