One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,11)(8,10)(9,12)(13,14,19,18)(15,20,24,28)(16,21,23,25)(17,26,27,22)(5,7)(6,9)(8,12)(10,11)(13,15,19,24)(14,20,18,28)(16,22,23,26)(17,25,27,21)(2,4)(13,16,19,23)(14,21,18,25)(15,17,24,27)(20,26,28,22)(6,10)(9,11)(13,14,19,18)(15,20,24,28)(16,25,23,21)(17,22,27,26)(7,12)(9,11)(13,17)(14,22)(15,23)(16,24)(18,26)(19,27)(20,21)(25,28) involution — undirectedA 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.