One vertex per element, one color per generator, with an edge from x to x·s.
(1,2) involution — undirected(4,6)(7,8,12,11)(9,15,17,13)(10,18,20,14)(16,21,19,22)(8,11)(13,15)(14,18)(21,22)(23,24,27,30)(25,28,33,31)(26,34,35,29)(32,37,38,36)(3,4)(5,6)(7,9,12,17)(8,13,11,15)(10,19,20,16)(14,22,18,21)(23,24)(25,31)(26,29)(27,30)(28,33)(32,37)(34,35)(36,38)(7,10,12,20)(8,14,11,18)(9,16,17,19)(13,21,15,22)(23,25)(24,28)(26,32)(27,33)(29,36)(30,31)(34,37)(35,38)(7,11,12,8)(9,15,17,13)(10,18,20,14)(16,22,19,21)(23,26,27,35)(24,29,30,34)(25,32,33,38)(28,36,31,37)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.