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