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