Some tips on how to improve the graphics (on Nvidia cards):
Also from that German forum (albeit I found it earlier on Guru3D, so don't know where it originates really).
You have to disable
Scaling and
MLAA in game for SGSSAA to work!
Some extra options you can try, Negative LOD Bias to Allow and set LOD Bias to -0.125 or more. This will enable sharpening on textures when the blur from using SSAA is excessive. Mind you, higher negative values will introduce texture shimmering!
I also turn on Gamma Correction, force on Anisotropic Filtering in drivers (as per the screenshot) and Vsync (limiting framerates to 58 fps to counter input lag).
I hear good things about disabling DoF and Grass in ETS 2 to improve the overall visuals. Haven't tried it yet, though.