Volleyball can be shot "ambient" on with balcony-mounted flash units triggered with wireless triggers. Volleyball is a speed sport...I have shot it at high school and NCAA levels...the "easy way out" is to stand behind the back line with a 200mm lens and shoot blocks and spikes as the players are within 2 feet of the net. That gives you a pretty easy focusing situation....try and shoot for a fast shutter speed, which will probably mean ISO 1600 or ISO 3200 at f/2.8 at 1/500 or 1/400.
Unless you are really proficient at high-speed focusing, I would not try to shoot volleyball from the side. However, some people, especially in Europe, seem to shoot volleyball from above, from the stands, which gives the photographer a good angle of view and a lot of possible angles and many different picture types, plus since the distance is relatively long, from the stands to the court, the focusing distances are easy to deal with.
***EDIT: Since I posted, you have posted,and I see you have a slowish Sigma zoom...that might be very challenging to shoot volleyball with.