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