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