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