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