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