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