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