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