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