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