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