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