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