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