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