Select all the curve objects you want to change the color. Modify the shapeColorIndex to get a new color.

Useful Color Index:

22 - Bright Yellow 23 - Desaturated Green 31 - Desaturated Pink

import maya.cmds as mc

crvShapeList = [] #Empty list
shapeColorIndex = 31

sel = mc.ls(sl=True) #Select all curve Objects

for crv in sel:
	crvShapeList.append(mc.listRelatives(crv, s=True)) # Gets all the shapes of the object in a list.

# crvShapeList is a list of a list so we need 2 FOR loops to get a singular shape
for crvShapes in crvShapeList: 
	for shape in crvShapes:
		mc.setAttr(shape + ".overrideEnabled", 1) 
		mc.setAttr(shape + ".overrideColor", shapeColorIndex)