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