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