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