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