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)(15,22,25,28)(16,21,18,26)(20,24,27,23)(5,6)(7,11)(8,10)(9,12)(13,15)(14,20)(16,23)(17,27)(18,24)(19,25)(21,28)(22,26) involution — undirected(2,4)(5,7,8,12)(6,9,10,11)(13,16,19,18)(14,21,17,26)(15,23,25,24)(20,28,27,22)(7,12)(9,11)(13,17,19,14)(15,22,25,28)(16,26,18,21)(20,24,27,23)(6,10)(9,11)(13,16,19,18)(14,21,17,26)(15,24,25,23)(20,22,27,28)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.