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