How can you predict relative Rf values of cis-trans isomers in thin layer chromatography?
Well, apparently I was wrong. 

In fact, the trans,trans isomer is adsorbed more strongly by the stationary phase because it is entirely planar. The cis,trans-isomer cannot adopt a planar conformation because of steric hindrance between the two phenyl rings. The non-coplanar geometry lowers the efficiency of interactions with the stationary phase, making it more mobile.  

So the cis,trans isomer has a higher Rf, and the trans,trans isomer has a lower Rf.