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