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