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