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