To find it definitively:
1. Consult your owner's manual: This is the best resource, as it will have a diagram showing the location of all fuses and relays.
2. Check the fuse box diagram: The fuse box cover (usually in the engine bay) usually has a diagram showing the location of fuses and relays. Look for one labeled "starter" or a similar designation (e.g., "IG" for ignition).
3. Look near the battery: Many Toyota models place relays in a box near the battery, often secured to the fender or inner fender well.
4. Look for a relay with thick gauge wires: The starter relay will have much thicker wires than most other relays, indicating it handles a high current.
Without access to your specific vehicle's documentation, pinpointing the exact location is impossible. Using the above steps should help you find it.