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