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