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