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