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