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)(15,20)(16,18)(23,27)(26,28) involution — undirected(5,7)(6,11)(8,10)(9,12)(13,14,17,19)(15,16,20,18)(22,25)(26,28)(7,8)(9,11)(13,15,17,20)(14,18,19,16)(21,22,24,25)(23,26,27,28)(1,2,3,4)(5,8,10,7)(6,11,12,9)(13,15)(14,16)(17,20)(18,19)(5,9,10,11)(6,7,12,8)(13,16)(14,15)(17,18)(19,20)(21,23)(22,26)(24,27)(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.