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