VSEPR theory is the Valency Shel Electron Pair Repulsion theory developed by Gillespie and Niholm (G N theory).
The geometrical structure of the molecule in terms of bonds and bond angles is explained in terms of the electron pairs (lone) on the central atoms and their repulsion on other atoms.
Both atoms have 6 electrons in the outermost orbit. sp2 hybridization.
See the diagram enclosed for the structure.
The lone pair on Sulfur repels the Oxygen atoms (electron pairs in that). So SO bonds are bent towards each other. As Oxygen atoms are electronegative, they do not repel each other.
As compared to this structure, CO2, has a linear structure. There are no lone pairs in CO2.