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