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