Development of mechanically flexible, and stretchable sensors based on electrical signals such as capacitance, voltage, and resistance, which can detect and simultaneously visualize large strain involved with human motion, is in great demand. Here, we demonstrate a highly stretchable, large strain capacitive sensor. This sensor can visualize the strain based on strain-responsive structural color (SC). Our device contains an elastomeric sensing film responsible for capacitance change upon strain in which a self-assembled block copolymer (BCP) photonic crystal (PC) film with 1-D periodic in-plane lamellae aligned parallel to the film surface is embedded for the efficient visualization of the strain. The capacitance change arises from dimension change of the elastomer film upon strain. The mechanochromic BCP PC film responds to the strain, giving rise to the SC change with strain. The initial red SC in a sensor is blue-shifted and turns blue when stretched to 100%, resulting in full colored SC alteration as a function of strain. Our BCP SC strain sensor exhibits fast strain response with multi-cycle reliability over 1000 times in both capacitance and SC change. This allows for efficient visible recognition of the strained positions by finger bending as well as poking with a sharp object.