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