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