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