The Qin Dynasty didn’t last very long (only 15 years) and so there wasn’t time to develop any special style of art. Mostly even experts can’t tell Qin Dynasty art from the Han Dynasty art that came next.
But archaeologists have excavated the tomb of one of the Qin Dynasty emperors, so we know that the stuff in that tomb comes from the Qin Dynasty. This tomb has a huge army of clay statues of soldiers, who were supposed to protect the dead emperor. You can see that the abstract designs and animals of the Zhou Dynasty have changed, and now art is becoming much more about representing people.
There were thousands of these clay soldiers in the tomb, and each one is a little bit different from the others.
Art in China (Oxford History of Art Series), by Craig Clunas (1997). Not especially easy, but a good introduction to the spirit of Chinese art. Warning: this one is not arranged in chronological order. Instead, it has chapters on sculpture, calligraphy, and so on.
The Incredible Story of China’s Buried Warriors, by Dorothy Hinshaw Patent (1999). For middle schoolers, about the terracotta army figures shown on this page. Great reviews!