Layout of Power lines to extension board (Temperature Sensor)
Its not a question of „who should be next to who“. 

If you want a design that is robust concerning EMI (I assume that‘s what you‘re after), then you have to defeat 3 enemies: 

1) inductive coupling (loop to loop). Current only flow in loops and loops carrying current affect each other. So you must figure out all loops and find a way not to interfere. Usually this is done by minimizing loop area. 

2) capacitive coupling. A plate of a plate capacitor influences the other plate through cap. coupling. Making use of this is called “shielding”. You can shield signals with e.g. a GND plane so they won’t be affected by cap. coupling.

3) galvanic coupling. The simplest form of interference happens when multiple currents (signals) share a line. The receiver of one signal will also see the other signals. This can be addressed with seperate lines for each signal or a star grounding concept. 

In your design, you could make GND as a plane (2 sided board) and you could use a shielded cable where you connect GND. You could also make the area (loop) between +5V and SIGNAL as small as possible.