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