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