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