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