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