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