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