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