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