The stress results in the SolidWorks Simulation study can be calculated using either Node or Element Values. You can change the display in your color chart by going to the Edit definition settings and changing the option in Advanced Options.
Stress values in a static simulation study are always calculated first at the Gauss points of each element. The nodal stress values at each node of every element are obtained by extrapolating the results from the Gauss points.
A node is usually commonly shared for several elements in a mesh. Each element can give slightly differing results from its neighboring element. Thus, there can exist more than one stress component that gives different values at the node.
The nodal stress values are generally the average of all contributing values from the adjacent elements at that specific node.
Alternatively, the software can plot the element stress values instead by averaging the stress internally at each gauss point. These stresses are known as non-averaging stresses since they are only done internally within the same element instead calculating with the neighbouring elements.