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)(15,18)(16,23)(17,20)(19,27)(21,28)(22,25)(24,26)(5,7)(6,9)(8,12)(10,11)(13,14,17,20)(15,18,21,28)(16,24,25,19)(22,26,23,27)(1,3,4,2)(13,15,18,20,17,21,28,14)(16,22,27,24,25,23,26,19)(6,10)(7,12)(13,16)(14,19)(15,22)(17,25)(18,27)(20,24)(21,23)(26,28) 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.