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