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