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