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