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