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