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)(1,2)(3,4)(13,14)(15,19)(16,20)(17,18)(21,27)(22,23)(24,28)(25,26) involution — undirected(6,9)(10,11)(14,17)(19,22)(20,25)(27,28) involution — undirected(5,6)(7,10)(8,9)(11,12)(13,15,18,23)(14,19,17,22)(16,24,26,21)(20,28,25,27)(5,7)(6,10)(8,12)(9,11)(13,16,18,26)(14,20,17,25)(15,21,23,24)(19,27,22,28)(13,17,18,14)(15,22,23,19)(16,25,26,20)(21,28,24,27)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.