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