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