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