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