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