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