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