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