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)(13,14,18,21)(15,23,24,17)(16,26,25,20)(19,22,27,28)(5,7,8,12)(6,9,10,11)(13,15)(14,17)(16,19)(18,24)(20,22)(21,23)(25,27)(26,28)(1,2,3,4)(6,10)(7,12)(13,16,27,24,18,25,19,15)(14,20,28,23,21,26,22,17)(6,10)(9,11)(14,21)(17,23)(20,26)(22,28) involution — undirected(13,17,19,26,18,23,27,20)(14,15,22,25,21,24,28,16)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.