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