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