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