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