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