Insulin is a naturally occurring hormone made by the pancreas that helps our body use or store the glucose (sugar) it gets from food. For people with diabetes, either the pancreas does not make enough insulin to meet the body's requirements, or the body cannot properly use the insulin that is made.
The yellow color in normal urine comes from a substance known as urochrome. Urochrome is also known as urobilin and is the result of hemoglobin breakdown. Hemoglobin is the protein in red blood cells that enables oxygen to be taken around the body.
Assuming that your assessment of the color is accurate, your urine is clear because it contains a lower concentration of the bilirubin breakdown products which cause urine to be yellow in the first place. If your physiology is otherwise normal, this is most typically related to how dilute your urine is.