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