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