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