Right-clicking in the assembly model area (with no parts highlighted) will bring up a menu with bottom choice "Hide All Reference Planes". That will hide all in assembly, including any subassembly and part planes that happen to be displayed.
To render:
1) quick way is click on "shade" (a 3-D solid yellow box in menu)
2) more detailed is to click on Format View which brings up a view setup window where you can choose (eg) phong shading, or set up rendered faces using jpeg images, change perspective, etc. Then you can save as image or print to distiller. You can also change background to an image, gradient, solid, set up reflection boxes, lighting...
Not quite 3D Studio but good for quick images.
Hint: don't save as jpeg image. The image quality really degrades. Better to save as tiff and then convert to jpeg with another program if required.