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