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