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