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