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