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