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