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