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