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