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