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