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