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