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