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