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