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