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