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