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