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