Below you can see the front-view size comparison of the Panasonic S1R and Olympus E-M1 II. The Olympus E-M1 II is clearly the smaller of the two cameras. Its body is 15 mm narrower, 19 mm shorter and 30 mm thinner than the Panasonic S1R.
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.