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