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