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