Leica SL has a
24.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Maestro II processor. On the other hand, Canon SX540 HS has a
20.0MP 1/2.3 (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features DIGIC 6 processor.
Another difference between these two cameras is that Leica SL's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the SL and SX540 HS sensor size comparison.
As seen above, Leica SL has a 30.8x Larger sensor area than Canon SX540 HS. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.