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